Continuous press

ABSTRACT

A continuous press is disclosed for simultaneously pressing and conveying a workpiece, such as the laminations for making plywood, through the press is a continuous manner. The continuous press comprises upper and lower platens upon which are mounted opposed sets of presser-conveyor rails, which are spaced apart to receive a workpiece therebetween. The presser-conveyor rails are mounted upon the respective platens by means of plural cams (circular eccentrics). Each set of rails drives a caterpillar belt and preferably a sheet belt which encircles the platen supporting that set of rails. The workpiece is interposed between the sheet belts. The rails in each set are divided into plural groups and the supporting eccentrics impart orbital motion to the rails in a polyphase arrangement, i.e, the motion of each group of rails is phase displaced from the motion of each group of rails. The two opposed sets of rails are actuated synchronously with the corresponding groups of rails and the two sets being 180* out of phase with each other.

United States Patent [191 Keaton Nov. 26, 1974 1 CONTINUOUS PRESS [76]Inventor: Clyde D. Keaton, 48 Dickinson St.,

Woodstown, NJ. 08098 22 Filed: Sept. 26, 1973 21 Appl. No.2 400,754

[52] US. Cl. 144/281 B, 100/154, 144/245 A,

156/583, 198/165, 198/203 [51] Int. Cl B27d 3/02, B27d 3/04 [58] Fieldof Search 156/583; 100/151, 154;

425/224, 364, 371, 394, 383, 406; 144/281 R, 281 A, 281 B, 281 C, 281 D,282, 283, 245 A; 198/165, 203

Primary Examiner-Andrew R. Juhasz Assistant ExaminerW. D. Bray Attorney,Agent, or Firm-Reising, Ethington and Perry [5 7 ABSTRACT A continuouspress is disclosed for simultaneously pressing and conveying aworkpiece, such as the laminations for making plywood, through the pressis a continuous manner. The continuous press comprises upper and lowerplatens upon which are mounted opposed sets of resser-conveyor rails,which are spaced apart to receive a workpiece therebetween. Thepresser-conveyor rails are mounted upon the respective platens by meansof plural cams (circular eccentrics). Each set of rails drives acaterpillar belt and preferably a sheet belt which encircles the platensupporting that set of rails. The workpiece is interposed between thesheet belts. The rails in each set are divided into plural groups andthe supporting eccentrics impart orbital motion to the rails in apolyphase arrangement, i.e, the motion of each group of rails is phasedisplaced from the motion of each group of rails. The two opposed setsof rails are actuated synchronously with the corresponding groups ofrails and the two sets being 180 out of phase with each other.

16 Claims, 8 Drawing Figures CONTINUOUS PRESS FIELD OF THE INVENTIONThis invention relates to apparatus for simultaneously pressing andconveying a workpiece; more particularly the invention relates toapparatus for continuous pressing of workpiece material while theworkpiece material is continuously conveyed through the apparatus.

BACKGROUND OF THE INVENTION The need for a continuous press capable ofapplying uniform and high pressure continuously to a workpiece while theworkpiece is conveyed through the press has long been recognized. Thereare numerous applications, such as the manufacture of laminated board orcomposition particle board, which is performed by a batch-process, eventhough a continuous process would be much more efficient if equipmentwere available. The prior art reflects a considerable effort to developa continuous press capable of applying high pressure uniformly over thesurface of a workpiece; however, it appears that heretofore the needfor'the continuous press has not been met.

Among the major problems in devising a high pressure continuous press isthe problem of obtaining uniform pressure over the area of the workpieceand the problem of producing continuous motion of the workpiece throughthe press under high pressure without overloading the bearings whichsupport the moving press members. Where anti-friction bearings of therolling type have been used, the small available bearing area results inhigh stresses and bearing failure and if slide bearings are utilized totake advantage of large bearing area, the sliding friction and resultingheat generation are excessive and the device is impractical.

One type of prior art continuous press utilizes a pair of oppositelyrotating chains of platens which are spaced apart to receive a workpiecetherebetween. The platens are aligned in the direction of movement andare driven continuously over guide rollers or sprockets. Pressure isapplied by hydraulic means to compress the workpiece between the opposedchains of platens and an anti-friction roller belt is provided on thebackside of each of the chain of platens to provide a roller typebearing for the chains of platens. Such apparatus is disclosed in theDyke Pat. No. 2,071,999 and also in the Lambert et al. Pat. No.2,490,819. A difficulty with this type of continuous press arises fromthe use of roller belts disposed between plane surfaces as the bearingmembers for supporting the continuously moving and heavily loadedplatens which engage the workpiece.

Another type of continuous press known in the prior art utilizes twooppositely disposed sets of parallel bars with the bar of each setextending in the direction of travel of the workpiece through the press.The workpiece is compressed between a pair of bars, one from each set,during a forward stroke of the pair of bars and then is compressedbetween a second pair of bars, one from each set, during a forwardstroke of the second pair of bars. The bars of the first pair are causedto separate and relieve pressure on the workpiece and to make a returnstroke during the forward stroke of the second pair. Similarly, thesecond pair of bars makes a return stroke during the forward stroke ofthe first pair. Apparatus of this type is set forth in the Maurer Pat.

No. 2,340,607 wherein the bars are driven in the forward stroke byfriction drive rollers and are released by the rollers at a flat spotthereon for a return stroke under the influence of a retracting spring.Another continuous press of this type is disclosed in the Maurer Pat.No. 2,289,022 wherein selected bars from the upper and lower set of barsare moved toward each other for compressing the workpiece therebetweenby means of a cam and follower arrangement and the same bars are movedin a forward and return strokev on a common carriage which is actuatedby a separate cam and follower arrangement. A difficulty with theapparatus of the former Maurer patent is the use of the friction drivefor advancing the bars; a difficulty with the apparatus of the latterMaurer patent is that it requires separate drive means for closing thepress bars and separate drive means for the feed or advance of the pressbars. Another prior art apparatus using the reciprocating bararrangement is shown in the Guyer Pat. No. 3,577,304. In the apparatusof this patent, a pair of opposed lifter bars are spaced apart to acceptthe workpiece therebetween and are mounted upon oppositely rotatingeccentrics. Upon each rotation of the eccentrics the lifter barssuccessively compress the workpiece therebetween and impart a forwardmotion to it; at the end of the forward stroke the lifter bars open anda pair of holding bars are closed thereagainst by spring pressure tomaintain compression of the workpiece in a dwellcondition while thelifter bars make a return stroke. A disadvantage of this arrangement isthat the workpiece 'is intermittently advanced through the press and thepressure on the workpiece is alternately applied by theeccentric-actuated lifter bars and the spring-actuated holding bars.

Another type of continuous press utilizes sliding friction to obtain alarge bearing area for support of the moving press members. In this typeof apparatus a pair of endless belts are disposed opposite each otherand each is mounted on suitable drive rollers. The portions of theendless belts which are disposed in opposition and which receive theworkpiece therebetween are respectively backed by rigid plates which inturn are supported by hydraulic plungers. To reduce the sliding frictionthe sheet of material having a low coefficient of friction is interposedbetween the moving belts and the respective backing plates. A continuouspress of this type is shown in the Pfeiffer Pat. No. 3,680,476.

SUMMARY OF THE INVENTION According to this invention there is provided acontinuous press which is capable of applying high pressure to aworkpiece while the workpiece is continuously conveyed through thepress. This is accomplished by opposed platens each of which carries aset of rails which face in a direction toward each other and which arespaced apart to accept the workpiece therebetween. The rails of each setare mounted on the respective platens with two rails being mounted uponcams rotatably supported on the platen. Drive means are provided forrotating the cams to impart orbital motion to the rails; the cams beingrotated in predetermined phase relationship so that a pair of rails, onefrom each set, move simultaneously in the respective orbital pathstoward the workpiece to press it therebetween and also move in thefeeding direction to advance the workpiece through the press.Additionally, the drive means imparts orbital motion to a second pair ofrails in such phase relation with each other and the first pair of railsso that the second pair are simultaneously moving away from theworkpiece and opposite the feeding direction while the rails of thefirst pair are in their pressingforward stroke. In other words, a firstpair of rails, one from each set, makes a press and advance stroke whileanother pair of rails, one from each set, makes a release and returnstroke. Accordingly, the workpiece is continuously pressed andcontinuously advances through the press.

Further, in accordance with the invention, the pressure applied to theworkpiece is maintained substantially constant as a function of timewhen the workpiece is fed through the press. This is accomplished byusing an hydraulic force applying means for supporting one of theplatens. The other platen may be fixedly mounted to the frame of thepress. The hydraulic force applying means is provided with an hydraulicaccumulator which serves to maintain a constant hydraulic pressure inthe force applying means despite the small cyclical variation in thespacing between pairs of rails during the press-advance stroke of eachpair. Further, according to the invention, the pressure applied to theworkpiece is maintained at a uniform value over the surface of theworkpiece. This is accomplished by means of a caterpillar belt orendless belt of crossbars. Such a caterpillar belt encircles the firstplaten and extends over the rails thereon with the crossbars spanningthe rails, so that the force exerted by one or more rails toward theworkpiece is applied through the bars to the workpiece. Similarly, sucha belt encircles the other platen and coacts with the rails thereof inthe same manner. Additionally, it is preferred to provide an endlesssheet belt encircling the caterpillar belt on the first platen and anendless sheet belt encircling the caterpillar belt on the second platen,in order to present an uninterrupted flat surface to both sides of theworkpiece.

Also, according to the invention, a continuous press is provided whichhas an exceedingly large load or pressure capacity. This is accomplishedby providing a large bearing area by mounting the rails directly on themotion imparting cams or eccentrics, so that each mounting constitutes ajournal bearing. This bearing area is multiplied by using multiple camsfor each rail. Also the cam shaft bearing area is maximized by spacingthe rails and disposing a cam shaft bearing between rails. In order toavoid gaps between the rails each rail is preferably of T-shapedcross-section, i.e., the head of the rail is wider than the web.

Further, in accordance with the invention, the variation in torquerequirements for driving the motion imparting cams is minimized. This isaccomplished by means of a polyphase arrangement of the cams and rails.In one embodiment the rails of each set are divided into two groups withall rails in the same group being moved in their respective orbitalpaths in phase with each other. The motion of the first group of railsis 180 out of phase with the motion of the other group of rails. Thisembodiment with two groups of rails in each set, and with the motion ofthe two groups of rails being of opposite phase, is referred hereinafterto a two-phase arrangement. In another preferred polyphase arrangementthe rails of each set are divided into three groups and the orbitalmotions of the three groups are displaced in phase from each other by120. In this arrangement which will be termed herein a three-phasearrangement, the motion of the second group of rails lags the motion ofthe first group of rails by and the motion of the third group of railslags the motion of the second group of rails by 120. The inventioncontemplates, in general, a polyphase arrangement of any desired numberof phases wherein the phase angle between successive phases is equal to360 divided by the number of phases or groups of rails.

Further, in accordance with the invention, the continuous press isadapted to provide variable feedrate without changing the pressureexerted by the press. This is accomplished by use of a common drive forall of the cams which in turn actuate the rails through both thepressure and advance strokes. Further, the synchronism of all cams isassured by providing a gear drive from the common drive means.

DETAILED DESCRIPTION A more complete understanding of this invention maybe obtained from the detailed description which follows, taken with theaccompanying drawings in which: i

FIG. 1 is a side elevation view of the continuous press of thisinvention;

FIG. 2 is a view taken on lines 22 of FIG. 1;

FIG. 3 is a view taken on lines 33 of FIG. 2;

FIG. 4 is a view taken on lines 4-4 of FIG. 1;

FIG. 5 shows a detail of construction;

FIG. 6 shows a temperature control system; and

FIGS. 7 and 8 show a modification.

Referring now to the drawings, there is shown an illustrative embodimentof the invention in a continuous press which is adapted forsimultaneously pressing and conveying a workpiece on a continuousthrough-put basis while maintaining the workpiece at a desiredtemperature during its travel through the press. It will be appreciatedas the description proceeds that the invention may be embodied in acontinuous press for a wide variety of applications. Although theinventive apparatus is capable of producing extremely high pressures onthe workpiece, it may also be used in applications where low pressure isrequired; further, whatever the pressure requirement may be, thecontinuous press also provides dimensional control for the workpiece.Additionally, the continuous press is adapted to provide heat treatmentor curing of the workpiece by temperature control for a predeterminedperiod during the travel of the workpiece through the press. Typicalapplications of the continuous press include the manufacture of largeplywood sheets on a continuous basis where the workpiece is relativelythick and wide and moderately high pressure is required, together withelevated temperature for curing. A typical applicationfor a smallworkpiece is that of manufacturing phenolic circuit boards which requireextremely high pressures and precise thickness control.

As shown in FIG. 1, the continuous press comprises a stationary base 6which supports an upper press memher 8 and a lower press member 12. Theupper press member is held in fixed position relative to the base member6, while the lower press member is supported upon a vertically movableplatform 16. An upper platen 10 carries an upper set of presser-conveyorrails 18 and a lower platen 14 carries a lower set of presserconveyorrails 20. The upper and lower sets of rails are disposed in face to facerelationship and are spaced apart to accept a workpiece 22 therebetween.It is noted that the workpiece 22 takes the form of a continuous thinand wide board, such as plywood, which is moved continuously through thepress in the direction indicated by the arrow.

Referring further to FIG. 1, the upper press member 8 is supported onthe base 6 by means of columns or corner posts 24 and horizontal beams26 supported on the posts. The platen is supported from the beams 26 bymeans of plural frame members 28 which are partially concealed by thecover plates 30 and 32. A shield member 34, partially broken away inFIG. 1, is mounted on the platen 10 outboard of the set of rails 18 onthe near side of the press as viewed in FIG. 1.

The upper press member 8 also includes an endless caterpillar belt 36which encircles the upper platen l0 and is supported upon a pair ofrollers 38 and 40, which in turn are supported on bearing plates 42 and44, which depend from the beams 26. Thecaterpillar belt 36 comprises amultiplicity of rigid bar links, each of which extends transversely ofthe press and spans the upper set of rails 18 in engagement therewith.The bar links 46 are disposed edge-to-edge and each is provided with atapered cross-section to provide clearance from the adjacent bar linksin passing over the rollers 38 and 40. Each bar link is secured to theadjacent one 'by means of a coil spring 48 which draws the adjacentlinks together to provide a substantially uninterrupted surface. (SeeFIG. 3 which shows the lower caterpillar belt of the same construction).

Referring further to the upper press member 8, an endless sheet belt 50is disposed over the caterpillar belt 36 to provide a continuous andsmooth facing to be presented to the workpiece. The sheet belt 50 issuitably constructed of stainless steel having a smooth and polishedouter surface which engages the upper surface of the workpiece. Thecaterpillar belt 36, and consequently the sheet belt 50, are driven onthe rollers 38 and 40 by the upper set of presser-conveyor bars 18which, along with the associated actuating mechanism, will bedescribed'subsequently.

Referring further to FIG. 1, the lower press member 12 will now bedescribed. This press member, in addition to the lower platen l4, andthe lower set of presserconveyor bars comprises an endless caterpillarbelt or link belt 52. The caterpillar belt 52 encircles the lower platenl4 and is supported upon a pair of rollers 54 and 56. The rollers aresupported upon bearing plates 58 and 60 which are mounted upon theplatform 16. The lower platen 14 is fixedly mounted upon the platform 16by frame members which are concealed by the cover plate 62. Thecaterpillar belt 52 is of the same construction as the previouslydescribed caterpillar belt 36 and has its surface disposed in engagementwith the lower set of presser-conveyor bars 20. An endless sheet belt 64encircles the caterpillar belt 52 and is supported upon a pair ofrollers 66 and 68. The rollers 66 and 68 are mounted upon hearing plates70 and 72 respectively, which in turn are mounted upon the platform 16.The endless sheet belt 64 is of the same construction as the sheet belt50 described above, and presents a smooth polished surface to the lowersurface of the workpiece 22. The sheet belt 64 is longer than the sheetbelt 50 and is supported on the separate rollers 66 and 68 to provide alower workpiece support surface at the input and output ends of thepress to facilitate loading and unloading.

The spacing of the press members will, of course, determine the openingor vertical dimension of the press throat which is defined by thespacing between the sheet belt 50 and the sheet belt 64 at the opposedsets of rails 18 and 20. The throat or press opening is preset inaccordance with the desired dimension of the workpiece and the settingis accomplished by raising or lowering the platform 16. For this purposethe platform 16 is mounted upon the base 6 by plural hydraulic actuatorsor jacks 74, 76 and 78. The hydraulic actuators are energized withhydraulic fluid from a pump 80 which is driven by an electric motor 82.In order to supply substantially constant pressure to the actuatorsdespite minor fluctuations in loading, an hydraulic accumulator 84,suitably of 'the bladder type, is connected serially in the supply line86 to the actuators which are connected in parallel. The hydraulicactuators are provided with double-acting pistons and a return line isconnected with the pump.

Referring now to FIGS. 2, 3 and 4, the upper and lower platens 10 and 14and the upper and lower sets of rails 18 and 20 and the associatedactuating mechanism will now be described. The lower platen 14, suitablyin the form of a flat plate, is fixedly mounted upon the platform 16 byframe members as previously mentioned. The platen 14 supports the lowerset of presserconveyor rails 20. All of the rails in the lower set areof the same construction, suitably of steel, and have a T-shapedcross-section. Each of the rails 20 has a web 90 which is narrower thanthe head 92 of the rail. Additionally, each of the rails is providedwith a fluid passage 94 in the head of the rail for purposes which willbe described later. As shown in FIG. 3, each of the rails 20 is providedwith multiple axially spaced bearing surfaces 96. These bearing surfacesare suitably provided by slots formed in the lower edge of the web 90 ofthe rail; alternatively, however, the surfaces 96 could be formed byholes drilled through the web of the rail and, if desired, provided withsuitable bearing inserts.

In order to support the individual rails 20 of the lower set of rails onthe lower platen l4 and to impart orbital motion to the individualrails, plural cams are interposed between each rail and the platen. Inthe embodiment of FIGS. 2, 3 and 4, a two-phase cam arrangement isemployed. In order to impart two-phase orbital motion to thepresser-conveyor rails the set of rails is divided into two groups witheach rail inthe first group designated by the reference character 20 andeach rail in the second group designated by the reference charater 20.Each rail is supported upon plural cams with the first group of rails 20being supported upon earns 98 and the second group of rails 20 beingsupported upon a second group of cams 98'. All of the cams 98 and 98which are axially aligned, such as those depicted in FIG. 2, will bereferred to as a set of cams and are mounted in fixed angularrelationupon a cam shaft 100 for rotation therewith. The set of camsdepicted in FIG. 2 are mounted upon the cam shaft 100, while additionalset of cams 98 and 98' are mounted upon additional cam shafts 100a,100b, 1000, 100d, 100e, and so on, depending upon the desired number ofsets of cams (see FIG. 4). The cam shaft 100 is supported on the platen14 by a pair of main journal bearings 101 and 103 and by a plurality ofintermediate journal bearings 105. It is noted that an intermediatejournal bearing 105 may be disposed between each pair of rails toprovide an extensive bearing area for the cam shaft.

As stated previously, the cams 98 and 98 are preferably of the sameconfiguration, namely, circular eccentric of the same size and of thesame eccentricity, i.e. the same throwv As can be seen from FIGS. 2 and4, the cams 98 are 180 out of phase with the cams 98, i.e., they aredisplaced by a predetermined phase angle of 180. Accordingly, in thepositions shown in FIG. 2, the rails are in their most extended positionin which the head of the rail is displaced a maximum distance from thecenter of the cam shaft 100 or the platen 14. At this given angularposition of the cam shaft 100 the rails 98' are in their most retractedposition so that the rail head is at its minimum distance from thecenter line of the cam shaft or the platen 14. The difference betweenthe maximum and minimum displacements of the head of the rail isreferred to herein as the throw of the eccentrio and is of course equalto the displacement of the center line of the eccentric itself from thecenter line of the cam shaft. It is noted that rotation of thecrankshaft 100 through an angular displacement of 180 causes the rails98 and 98' to reverse the positions shown in FIG. 2. Rotation of the camshaft 100 imparts orbital motion to each of the rails 98 and 98 and, ofcourse, a circular orbital path is described by any given point on arail for each revolution of the cam shaft. It is further noted withreference to FIG. 2, taking the angular position of the cam shaft 100,as shown, to be the reference position, that 90 rotation of the camshaft either clockwise to counterclockwise will change the positions ofboth rails 98 and 98 so that they are at equal displacements from thecenter line of the cam shaft, i.e., the working faces 96 of the railsare in alignment with each other. This relative position of the rails 98and 98' may be referred to as the transfer position because it is atthis point in rotation of the cam shaft that the rails 20 disengage thecaterpillar belt 52 and the rails 20 engage the caterpillar belt 52, orvice versa, and consequently the work applied to the workpiece isshifted from one set of rails to the other. Further examination of theset of rails 20 and 20 in FIGS. 2 will aid in further understanding ofthe pressure and motion imparted by the presser-conveyor rails to theworkpiece. With the cam shaft 100 rotating in a clockwise direction asviewed from the righthand end, the rail 20 will be moving forward(direction of the arrow in FIG. 1 and into the paper in FIG. 2),immediately after it passes its top dead center position in the rotationof the cam shaft 100. This portion of the orbital path of the rail 20carries the caterpillar belt 52 in the forward direction and henceadvances the workpiece 22 through the press. At the same time the rail20 is disengaged from the caterpillar belt 52 and immediately afterpassing its bottom dead center position this rail is moving rearwardly(out of the paper in FIG. 2) and upwardly. Accordingly the rotation ofthe cam shaft 100 in the clockwise direction as viewed from therighthand end in FIG. 2, continuously advances the workpiece through thepress in the feeding direction of the arrow shown in FIG. 1. The amountof advancement of the workpiece for each revolution of the cam shaftdepends upon the throw of the cams or eccentrics and the forward motionof the workpiece is substantially uniform.

Referring further to FIG. 2 the upper platen 10, the set of rails 18 andthe associated actuating mechanism will now be described. The assemblyis basically the same as that just described with reference to the lowerplaten l4 and the rails 20 and 20' andaccordingly only brief descriptionis required. The set of rails 18, for convenience of description, isdivided into a first group including rails 18 and a second groupincluding rails 18. Each individual rail is of the same construction asthe rails 20 in the lower set. Each rail is similarly mounted uponplural cams as illustrated in FIG. 3 with respect to rails 20. Each rail18 is supported upon a cam (circular eccentric) 104 and each rail 18 issupported upon a cam (circular eccentric) 104. The set of camscomprising cams 104 and 104' which are axially aligned with each otherare mounted upon a cam shaft 106 for rotation therewith. The cam shaft106 is supported on the platen 10 by a pair of main journal bearings 107and 108 and by a plurality of intermediate journal bearings 109. It isnoted that an intermediate journal bearing 109 may be disposed betweeneach pair of rails to provide an extensive bearing area for the camshaft.

Referring further to the cams 104 and 104, as shown in FIG. 2, thesecams are angularly displaced from each other on the cam shaft by a phaseangle of 180. Further, a phase relation is pre-established between thefirst group of cams 104 and the first group of cams 98 and hence betweenthe first group of rails 18 and the first group of rails 20. In thispredetermined phase relationship, as shown in FIG. 2, the motion of therail 18 is 180 out of phase with the motion of the rail 20. Similarly,the motion'of the rail 18' is 180 out of phase with the motion of therail 20'. In other words, when rail 20 is in its top dead centerposition the rail 18 is in its bottom dead center position; also asshown, the rail 20 is in its bottom dead center position while the rail18 is in its top dead center position.

The coaction of the set of rails 20 and 20' with the set of rails 18 and18 will now be appreciated. In order to advance the workpiece 22 throughthe press the cam shaft is rotated ina clockwise direction as viewedfrom the righthand end in FIG. 2 and the cam shaft 106 is rotated in acounter clockwise direction as viewed from the righthand end in FIG. 2.During each revolution of the cam shafts 100 and 106 the presserconveyorrails 18 and 20 will move toward each other and in a forward direction,clamping the workpiece therebetween and advancing it through the press.At the same point where the rails 18 and 20 release the workpiece therails 18 and 20 will engage the workpiece in their motion toward eachother and in the forward direction, i.e., the transfer point occurswhere the work shifts from rails 18 and 20 to rails 18' and 20'. It isobserved that in the circular orbital motion of the rails 18 and 20 thecomponents of motion toward and away from each other is a harmonicmotion with cyclical variation in the spacing between the rails 18 and20 at a frequency corresponding to the speed of rotation of the camshafts. Further, it is noted that when the rail 20 is at its top deadcenter and the rail 18 is at its bottom dead center, the rails are atminimum spacing and this minimum spacing is less than the spacing at thetransfer point when the rails 18' and 20' engage the workpiece.Similarly, before the next transfer point occurs the rails 18 and 20will have passed through their point of minimum spacing. As aconsequence cyclical variation in the spacing between the rails 18 and20 and the out-of-phase cyclical variations in the spacing between therails 18' and 20, the pressure transmitted to the workpiece through thecaterpillar belts 36 and 52 is of an oscillatory character of very smallamplitude and having a frequency corresponding to twice the rotationalspeed of the cam shafts. This cyclical variation in pressure iseliminated by the action of the hydraulic accumulator 80 so that thepressure applied to the workpiece is substantially constant in value.

v In order to drive the cam shafts in synchronism and to maintain properphase relationship a drive train is provided as shown in FIGS. 2 and 4.A single prime mover (not shown) is coupled to the input shaft 110 andthe prime mover is preferably of variable speed type so that thefeedrate of the press may be adjusted. The input shaft 110 is coupledthrough beveled gears 112 and 114 to a splined counter shaft 116 whichis suitably journalled in the upper and lower platens and 14. Thesplined shaft arrangement accommodates the change in spacing between theplatens when the press is adjusted for different size workpieces. Thecountershaft 116 is coupled through beveled gears 118 and 120 to a stubshaft 122 which is mounted in a hearing plate 124. A pinion gear 126 onthe stub shaft 122 meshes on one side with a driven gear 128 mounted onthe cam shaft 100. The pinion gear 126 meshes on the other side with adriven gear 130 which is mounted on the cam shaft 100e.

In a similar manner, rotational drive is imparted to the plural camshafts mounted on the upper platen 10. This drive train is shown in parton FIG. 2 with the counter shaft 116 connected through beveled gears 134and 136 to a stub shaft 138, which is mounted on a bearing plate 140.The stub shaft is connected to a pinion gear and a pair of driven gearson opposite sides thereof in the same manner as the pinion gear 126 isconnected to the driven gears 128 and 130, as shown in FIG. 4. Referringto FIG. 2, the aforementioned pinion gear meshes with a driven gear 142(which is one of the aforementioned driven gears), which is drivinglyconnected to the cam shaft 106. As previously explained, there are aplurality of cam shafts mounted on the upper platen 10, but only one ofthese cam shafts 106 is shown in the drawing, (see FIG. 2). The drivingarrangement for the plural cam shafts in the upper platen 10 is exactlythe same as the drive train for the plural cam shafts 100, 100a, 100b,etc. in the lower platen 14, which will now be described further withreference to FIG. 4.

As shown in FIG. 4, and as previously described, the drive pinion I26meshes with driven gears 128 and 130. With the input shaft 110 rotatingclockwise, as viewed from the righthand end in FIG. 2, it can be seenthat the pinion gear 126 will be rotating clockwise as viewed from thelower end in FIG. 4. Consequently driven gear 128 and the cam shaft 100are rotated counterclockwise, as viewed from the lower end. A drive gear150 is keyed to the cam shaft 100 and an idler gear 152 is mounted onthe cam shaft 100 and rotatable with respect thereto. In a similarfashion the cam shaft 10% carries a driving gear 15% and an idler gear152b. Similarly, on cam shaft 1000, there is a driving gear 150C and anidler gear 152C. The other cam shafts also carry driving and idler gearsbut before referring thereto it is noted that the cam shaft 100e is alsodriven counterclockwise, as viewed from the lower end. The cam shaftl00e carries a driving gear l50e and an idler gear 152e. These drivingand idler gears on cam shaft 100e mesh with idler and driving gears 152dand d on the cam shaft 100d. Similarly, the cam shaft 100f carries idlerand driving gears which mesh with the adjacent gears on cam shaft 100a.Thus, all of the cam shafts 100, 100a, 100b, etc. are driven in acounterclockwise direction viewed from the lower end, which is theproper direction to advance the workpiece through the press. It is notedthat the cam shaft drive arrangement just described permits a maximumnumber of cam shafts to be mounted on the platen and hence a maximumbearing area for support of the rails. The cam shaft drive arrangementfor the cam shafts on the upper platen 10 is identical to that justdescribed with reference to FIG. 4, it being understood, however, thatthe cam shafts in the platen 10 are driven in the opposite directionfrom those in the lower platen 14.

Referring now to FIG. 5, there is shown a detail of construction whichis employed in the embodiment depicted in FIG. 1. It is noted that therails 18 and 20, at the input end of the press, are formed withdivergent surfaces on the respective heads of the rails. Thisconstruction provides a wider input area which facilitates the entry ofthe leading end of the workpiece and causes compaction of a bulkymaterial over a desired distance of travel. Further, it is noted in FIG.5 that the set of rails 18 are provided with bearing surfaces 96'similar to bearing surfaces 96, provided in the set of rails 20. Sincethe rails 18 would tend to fall off the cams 104 in the absence of aworkpiece in the press, a retainer element 106 is inserted in theopening in the rail above each cam. 1

Referring now to-FIG. 6, a temperature regulating system is illustratedfor provided for either heating or cooling of the workpiece during itstravel through the press. FIG. 6 is a plan view of the lower set ofrails 20 and 20. As previously noted, each of the rails is provided witha fluid passage 94 in the head of the rail (see FIG. 2). Such fluidpassages are adapted for the circulation of a heat exchange fluid, suchas oil, through the rails to maintain the rails at a desiredtemperature. The fluid circulation system includes a source of hightemperature oil which is connected by a supply conduit 162 to an inletheader 164. The header 164 has a plurality of outlets, one for eachrail, which are connected respectively through flexible conduits 166 tothe passages in the rails. The outlet ends of the passages in the railsare connected respectively through flexible conduits 168 to pluralinlets of an outlet header 170. A return conduit 172 is connectedbetween the header and the return fitting of the source 160. In asimilar manner a source 174 of low temperature oil is connected througha supply conduit 176 to the inlet header 164. The circulation iscompleted through the passages in the rails to the outlet header 170 andhence through a return conduit 178 to a return fitting on the source174. In order to selectively connect either the heating fluid or thecooling fluid, control valves 180 and 182 are connected respectivelywith the sources 160 and 174. The connection of the conduits to therails is also illustrated in part in FIG. 1. It is noted that the supplyconduit 176 is provided ,with a slip fitting 182 to accommodate theadjustment of the position of the lower platen 14 relative to the base.Similarly, the return conduit 178 is provided with a slip fitting 184.In the like manner the supply conduit 162 and the return conduit 172 areprovided with slip fittings (not shown). A similar temperature controlsystem is provided for the rails 18 in the upper platen 10, so that heatexchange means through the rails is provided on both the upper and lowersurfaces of the workpiece.

An additional embodiment of the invention is illustrated in FIGS. 7 and8. In this embodiment a threephase arrangement of the cams is employedto realize certain advantages which will be discussed subsequently. Inthe three-phase arrangement, the cams of a given set of cams are dividedinto three groups, and the cams in each group are displaced in phasefrom each other group by 120. This is illustrated in FIGS. 7 and 8,wherein a lower set of cams 200 includes a first cam 202, a second cam204, and a third cam 206. Each of the cams is mounted on a cam shaft 208for rotation therewith. Preferably the cams are in the form of circulareccentrics, as discussed with reference to the embodiment of FIGS. 1 and2. As illustrated, the cam 202 is then at its top dead center positionwhile cam 204 is displaced 120 clockwise therefrom and cam 206 isdisplaced l20 counterclockwise therefrom. As shown in FIG. 8, the rails210, 212 and 214 are supported respectively on the cams 202, 204 and206. With the cam 202 in its top dead center position the rail 210engages the caterpillar belt 216 while the rails 212 and 214 are in anintermediate position. With the cam shaft rotating clockwise, as viewedfrom the righthand end in FIG. 8, continued rotation from the positionshown will cause rail 210 to move forwardly and downwardly while rail204 will move further forwardly and downwardly and at the same time rail214 will continue moving upwardly and forwardly. It is noted that rails216 and 214 will reach the same height at 60 displacement after the topdead center position of rail 210. In the three-phase arrangement thetransfer points are separated by only 60 (as compared to 90 for thetwo-phase). FIG. 7 also illustrates the phase relation of the cams inthe upper platen 10. The cam 220 is in its bottom dead center positionwhen the cam 202 is in its top dead center position. The cam 222 isdisplaced 120 counterclockwise from the cam 220 and the cam 224isdisplaced 120 clockwise from the cam 220. This set of cams is mounted ona cam shaft 226 for rotation therewith. The cam shaft 226 is rotated ina direction opposite from the rotational direction of the cam shaft 208;consequently, the cams 220 and 202 first move toward each other to clampand advance the workpiece, then the cams 206 and 224 move toward eachother to clamp and advance the workpiece, followed by the cams 222 and204 which move toward each other to clamp and advance the workpiece, thetransfer points being spaced at 60.

The three-phase arrangement provides a significant advantage in that thetorque required to drive the press is caused to be more uniform byreason of the fact that the transfer points are spaced closer togetherin the angular displacement. Furthermore, the amplitude of the cyclicalpressure fluctuations (which are eliminated by the hydraulicaccumulator) are decreased relative to the two-phase arrangement becausethere is smaller difference in the minimum spacing between opposed camsand the spacing when the opposed cams are at their transfer points. Itwill now be appreciated that a multiple phase arrangement of higherorder, such as a six-phase, will lend further advantage in respect tothe above-mentioned operation.

In the operation of the continuous press the feedrate is suitablyestablished by adjusting the speed of the prime mover. Because of thedrive train previously described, synchronism and phase relationshipsare inherently maintained and the pressure applied by the press to theworkpiece remains unaffected. It is noted that feedrate is also affectedby the throw or eccentricity of the cams and for a given application theeccentricity and drive speed may be correlated to obtain the desiredfeedrate.

The illustrative embodiment described herein is provided with asubstantially uniform gap through the press, as may be used for plywoodor the like. However, for certain applications involving materialshaving a high bulk factor which are to be compressed, the platens may bedisposed at an angle so that the gap through the press becomesprogressively smaller as the material is thereby gradually compacted.

Although the description of this invention has been given with respectto a particular embodiment, it is not to be construed in a limitingsense. Many variations and modifications will now occur to those skilledin the art. For a definition of the invention reference is made to theappended claims.

The embodiments of the present invention in which an exclusive propertyor privilege is claimed are defined as follows:

1. Apparatus for simultaneously pressing and conveying a workpiececomprising a first platen having plural cams rotatably mounted thereon,a first set of rails disposed side-by-side with each rail mounted upon adifferent one of the earns, a second platen having plural cams rotatablymounted thereon, a second set of rails disposed side-by-side with eachrail of the-second set mounted upon a different one of the cams on thesecond platen, the first and second set of rails facing in a directiontoward each other and spaced apart to accept a workpiece therebetween,means for rotating the cams to impart orbital motion to the rails, saidorbital motion being in a plane parallel to said direction, the orbitalmotion of the first set of rails being clockwise and .the orbital motionof the second set of rails being counterclockwise, said orbital motionof a first rail in the first set of rails being of opposite phase fromthe orbital motion of a first rail in the second set of rails, saidorbital motion of a second rail in the first set of rails being phasedisplaced by a predetermined phase angle from the phase of the orbitalmotion of said first rail in the first set of rails, and said orbitalmotion of a second rail in the second set of rails being phase displacedby said predetermined phase angle from the phase of the orbital motionof said first rail in the second set of rails.

2. The invention as defined in claim 1 wherein said predetermined phaseangle is equal to 360 divided by the number of rails in the first set ofrails which are out of phase with each other.

3. The invention as defined in claim 2 wherein the number of rails inthe first set of rails which are out of phase of each other is equal totwo.

4. The invention as defined in claim 2 wherein the number of rails inthe first set of rails which are out of phase of each other is equal tothree.

5. The invention as defined in claim 1 wherein at least one of saidplatens is yieldably supported relative to the other whereby thedistance between the first rail in the first set of rails and the firstrail in the second set of rails remains substantially constantthroughout the orbital motion of the last mentioned rails relative tosaid platens.

6. The invention as defined in claim wherein said first platen issupported in fixed position, hydraulic means supporting said secondplaten, said hydraulic means including an hydraulic accumulator toprovide yieldable support for said second platen.

' 7. The invention as defined in claim 5 including first and secondrollers disposed at opposite ends respectively of said first set ofrails, a first endless link belt supported on said first and secondrollers and encircling said first platen and first set of rails and inengagement with said first set of rails, third and fourth rollersdisposed at opposite ends respectively of said second set of rails, asecond endless link belt supported on said third and fourth rollers andencircling said second set of rails and said second platen and inengagement with said second set of rails, said link belts eachcomprising multiple links in the form of rigid bars spanning therespective sets of rails.

8. The invention as defined in claim 7 wherein each of said rigid barsis disposed in edge-to-edge contact with the adjacent bars to present asubstantially continuous surface, said bars being of taperedcross-section to provide clearance from adjacent bars when passingaround said rollers.

9. The invention as defined in claim 7, including a first endless sheetbelt encircling said first endless link belt and movable therewith and asecond endless sheet belt encircling said second endless link belt andmovable therewith. j

10. The invention as defined in claim 5, wherein each rail is mountedupon multiple cams spaced longitudinally of each rail, all camssupporting a given rail being connected with said means and beingrotated in phase with each other.

11. The invention as defined in claim 5 including a first cam shaftmounted on said first platen and connected to the cams mounted thereon,a second cam shaft mounted on said second platen and connected to thecams mounted thereon, and separate bearing means for each cam shaftadjacent each rail of the first set of rails.

12. The invention as defined in claim 11, wherein each rail in saidfirst set of rails includes a web of narrower cross-section than thehead of said rail whereby the webs of the rails may be separated by saidbearing means and the heads of adjacent rails may be more closely spacedthan the webs.

13. The invention as defined in claim 5 wherein said cam is an eccentricof circular curvature whereby said orbital motion of each rail describesa circular orbit.

14. The invention as defined inclaim 11, comprising a prime mover,mechanical coupling means connected between the first cam shaft and theprime mover and connected between the second cam shaft and the primemover, whereby said rails are moved in synchronism in their respectiveorbital paths.

15. The invention as defined in claim 14, wherein,

said mechanical coupling means comprises a first drive means connectedbetween said primemover and said first cam shaft for driving thecamshaft in one direction, and second drive means connected. betweensaid prime mover and said second cam shaft for driving said cam shaft inthe opposite direction.

16. The invention as defined in claim 15, including plural additionalcam'shafts rotatably mounted in said first platen, each additional camshaft including a separate cam coacting with each rail in the first setof rails, said first cam shaft and each additional cam shaft having adrive gear nonrotatably mounted thereon and an idler gearrotatablymounted thereon, the drive gears and idler gears all having the samenumber of teeth, said first cam shaft and one of said plurality ofadditional cam shafts being connected to said first drive means forrotation in opposite directions, the drive gear on each cam shaftmeshing with the idler gear on each adjacent cam shaft, whereby all ofthe cam shafts rotate in the same direction.

1. Apparatus for simultaneously pressing and conveying a workpiececomprising a first platen having plural cams rotatably mounted thereon,a first set of rails disposed side-by-side with each rail mounted upon adifferent one of the cams, a second platen having plural cams rotatablymounted thereon, a second set of rails disposed side-by-side with eachrail of the second set mounted upon a different one of the cams on thesecond platen, the first and second set of rails facing in a directiontoward each other and spaced apart to accept a workpiece therebetween,means for rotating the cams to impart orbital motion to the rails, saidorbital motion being in a plane parallel to said direction, the orbitalmotion of the first set of rails being clockwise and the orbital motionof the second set of rails being counterclockwise, said orbital motionof a first rail in the first set of rails being of opposite phase fromthe orbital motion of a first rail in the second set of rails, saidorbital motion of a second rail in the first set of rails being phasedisplaced by a predetermined phase angle from the phase of the orbitalmotion of said first rail in the first set of rails, and said orbitalmotion of a second rail in the second set of rails being phase displacedby said predetermined phase angle from the phase of the orbital motionof said first rail in the second set of rails.
 2. The invention asdefined in claim 1 wherein said predetermined phase angle is equal to360* divided by the number of rails in the first set of rails which areout of phase with each other.
 3. The invention as defined in claim 2wherein the number of rails in the first set of rails which are out ofphase of each other is equal to two.
 4. The invention as defined inclaim 2 whereiN the number of rails in the first set of rails which areout of phase of each other is equal to three.
 5. The invention asdefined in claim 1 wherein at least one of said platens is yieldablysupported relative to the other whereby the distance between the firstrail in the first set of rails and the first rail in the second set ofrails remains substantially constant throughout the orbital motion ofthe last mentioned rails relative to said platens.
 6. The invention asdefined in claim 5 wherein said first platen is supported in fixedposition, hydraulic means supporting said second platen, said hydraulicmeans including an hydraulic accumulator to provide yieldable supportfor said second platen.
 7. The invention as defined in claim 5 includingfirst and second rollers disposed at opposite ends respectively of saidfirst set of rails, a first endless link belt supported on said firstand second rollers and encircling said first platen and first set ofrails and in engagement with said first set of rails, third and fourthrollers disposed at opposite ends respectively of said second set ofrails, a second endless link belt supported on said third and fourthrollers and encircling said second set of rails and said second platenand in engagement with said second set of rails, said link belts eachcomprising multiple links in the form of rigid bars spanning therespective sets of rails.
 8. The invention as defined in claim 7 whereineach of said rigid bars is disposed in edge-to-edge contact with theadjacent bars to present a substantially continuous surface, said barsbeing of tapered cross-section to provide clearance from the adjacentbars when passing around said rollers.
 9. The invention as defined inclaim 7, including a first endless sheet belt encircling said firstendless link belt and movable therewith and a second endless sheet beltencircling said second endless link belt and movable therewith.
 10. Theinvention as defined in claim 5, wherein each rail is mounted uponmultiple cams spaced longitudinally of each rail, all cams supporting agiven rail being connected with said means and being rotated in phasewith each other.
 11. The invention as defined in claim 5 including afirst cam shaft mounted on said first platen and connected to the camsmounted thereon, a second cam shaft mounted on said second platen andconnected to the cams mounted thereon, and separate bearing means foreach cam shaft adjacent each rail of the first set of rails.
 12. Theinvention as defined in claim 11, wherein each rail in said first set ofrails includes a web of narrower cross-section than the head of saidrail whereby the webs of the rails may be separated by said bearingmeans and the heads of adjacent rails may be more closely spaced thanthe webs.
 13. The invention as defined in claim 5 wherein said cam is aneccentric of circular curvature whereby said orbital motion of each raildescribes a circular orbit.
 14. The invention as defined in claim 11,comprising a prime mover, mechanical coupling means connected betweenthe first cam shaft and the prime mover and connected between the secondcam shaft and the prime mover, whereby said rails are moved insynchronism in their respective orbital paths.
 15. The invention asdefined in claim 14, wherein said mechanical coupling means comprises afirst drive means connected between said prime mover and said first camshaft for driving the cam shaft in one direction, and second drive meansconnected between said prime mover and said second cam shaft for drivingsaid cam shaft in the opposite direction.
 16. The invention as definedin claim 15, including plural additional cam shafts rotatably mounted insaid first platen, each additional cam shaft including a separate camcoacting with each rail in the first set of rails, said first cam shaftand each additional cam shaft having a drive gear nonrotatably mountedthereon and an idler gear rotatably mounted thereon, the drive gears andidler gears all having The same number of teeth, said first cam shaftand one of said plurality of additional cam shafts being connected tosaid first drive means for rotation in opposite directions, the drivegear on each cam shaft meshing with the idler gear on each adjacent camshaft, whereby all of the cam shafts rotate in the same direction.